The purpose of the Clinical Core is to provide biological specimens and behavioral data to all of the individual research projects. This core will be located in Indianapolis. Core research personnel will enroll and maintain the cohort of middle adolescent female research subjects over the five year duration of the center, collect all required biological samples (genitourinary swabs, endocervical secretions, vaginal lavages, urine, cervical biopsies, and blood), behavioral information (self-administered questionnaires and personal interviews), and provide interim reproductive health examinations and data collection to facilitate subject retention. Research personnel will include research coordinator, research nurse practitioner, and two Disease Intervention Specialists (DIS) from the Marion Country Health Department. The research nurse will obtain all biological specimens. DIS will perform two important fieldwork functions: (1) contact sexual partners of subjects to obtained personal information, urine samples, provide appropriate antibiotic treatment when partners of infected women prefer to be treated outside of the Marion County STD Clinic (Bell Flower); (2) weekly contact with all subjects during the three month period of intense data collection to obtain urine samples and self-directed vaginal swabs, personal behavioral diaries and interview information.